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11 allergy-inducing pollen producers

By: Russell McLendon on April 21, 2011, 7:30 a.m.
Birch forest

Photo: saaby/Flickr

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Birches rank second only to oaks among allergenic trees, according to's Pollen Library. They form fast-growing forests that quickly colonize new habitat, becoming increasingly allergenic as they multiply.

Habitat: Europe, Asia and North America (especially east of the Rocky Mountains)

Description: Tall, narrow trees growing 60 to 100 feet high, often with scaly, papery bark

Allergenicity: Moderate to severe

Allergy season: Spring

Tips: Birches are at their worst in large numbers, but if you're allergic, actual birch trees may not be your only problem: Proteins in many raw fruits and vegetables resemble birch pollen enough to trigger allergies in some people. These include almonds, apples, cherries, peaches and walnuts, but fortunately the proteins can be denatured by cooking.